Association between serum Klotho levels and hypothyroidism in older adults: NHANES 2007-2012

Whether Klotho plays any role in hypothyroidism is unknown. This study aimed to determine the relationship between serum Klotho levels and hypothyroidism in older adults. From the 2007 to 2012 National Health and Nutrition Examination Survey (NHANES), 1444 older adults aged 65-79 were included in this cross-sectional study. Hypothyroidism was diagnosed using participants' reports of current medications and TSH tests. Klotho was measured using an enzyme-linked immunosorbent assay. The relationship between serum Klotho levels and hypothyroidism in older people was analyzed by one-way analysis of variance, multiple linear regression models, subgroup analyses, interaction tests, smoothed curve fitting, and threshold effects. A total of 209 (14.47%) participants were identified as having hypothyroidism. Serum Klotho (ln transformation) is independently and significantly negatively associated with the risk of hypothyroidism after complete adjustment for confounders (OR = 0.49, 95% CI 0.31-0.80; P = 0.0039). The results remained stable based on subgroup analyses and interaction tests. However, we observed an inverted U-shaped curve between the two using a smoothed curve fitting in the subgroups of 70 < age ≤ 75 years and females, with inflection points of 6.26 and 6.17, respectively. The results of our study indicate that serum Klotho levels negatively correlate with hypothyroidism among older adults.

Inverse association of the systemic immune-inflammation index with serum anti-ageing protein Klotho levels in individuals with osteoarthritis: A cross-sectional study

BACKGROUND

The association between the systemic immune-inflammation index (SII) and the serum soluble-Klotho concentration (pg/ml) in osteoarthritis (OA) patients is unknown. This study aimed to investigate the relationship between the SII and serum soluble-Klotho levels in OA patients.

METHODS

All study data were obtained from the National Health and Nutrition Examination Survey (NHANES) database (n = 1852 OA patients; age range = 40-79 years). The SII and serum Klotho measurement data are from the NHANES mobile examination centre. The SII values were divided into quartiles (Q1-4: 0.02-3.36, 3.36-4.78, 4.79-6.70, and 6.70-41.75). A multivariate linear regression model was constructed to evaluate the association between the SII and serum Klotho levels in OA patients; interaction tests were conducted to test the stability of the statistical results.

RESULTS

Multivariate linear regression revealed a negative linear relationship between the SII and serum Klotho concentration in OA patients (β = -6.05; 95% CI: -9.72, -2.39). Compared to Q1, Q4 was associated with lower serum Klotho concentrations (β = -59.93; 95% CI: -96.57, -23.28). Compared with that of Q1, the β value of Q2-Q4 showed a downwards trend as the SII increased (Ptrend <0.001). The stratified analysis results indicated that the SII had a greater sensitivity in predicting serum Klotho concentrations in OA patients aged 60-79 years (Pinteraction = 0.028).

CONCLUSIONS

There was a significant negative linear correlation between the SII and serum Klotho concentration in OA patients. The SII can serve as a predictive indicator of serum Klotho concentrations in OA patients. Klotho may be a potential anti-inflammatory drug for OA treatment.

Patients With Coronary Microvascular Dysfunction Have Less Circulating α-Klotho

BACKGROUND

Coronary microvascular dysfunction (CMD) represents an early functional characteristic of coronary vascular aging. Klotho (α-klotho) is a circulating protein inversely linked to physiological aging. We examined low klotho as a potential marker for vascular aging in patients with CMD and no coronary artery disease.

METHODS AND RESULTS

Patients undergoing nonurgent angiogram for chest pain who had no coronary artery disease underwent invasive coronary microvascular and endothelial function testing. CMD was defined by ≤50% increase in coronary blood flow (percentage change in coronary blood flow) in response to intracoronary acetylcholine or coronary flow reserve ≤2. Fresh arterial whole blood was used to analyze circulating endothelial progenitor cells with flow cytometry. Stored arterial plasma was used for klotho analysis by ELISA. Participants with CMD (n=62) were compared with those without CMD (n=36). Those with CMD were age 55±10 years (versus 51±11 years; P=0.07) and 73% women (versus 81%; P=0.38). Traditional risk factors for coronary artery disease were similar between groups. Patients with CMD had less klotho (0.88±1.50 versus 1.75±2.38 ng/mL; P=0.03), and the odds of low klotho in CMD were significant in a logistic regression model after adjusting for traditional cardiovascular risk factors (odds ratio [OR], 0.80 [95% CI, 0.636-0.996]; P=0.05). Higher klotho was associated with higher numbers of endothelial progenitor cells with vascular regenerative potential (CD34+ and CD34+CD133+KDR+). Among a subgroup of patients with atherosclerotic cardiovascular disease risk <5% (n=58), CMD remained associated with lower klotho (OR, 0.80 [95% CI, 0.636-0.996]; P=0.047).

CONCLUSIONS

Klotho may be a biomarker for CMD and may be a therapeutic target for groups of patients without significant traditional cardiovascular risk.

Serum klotho associated with thyroid hormone in adults: A population-based cross-sectional research

BACKGROUND AND STUDY AIM

The klotho protein, a multifunctional protein, has been shown to be associated with a wide range of endocrine diseases and has been linked to thyroid tumourigenesis. However, the relationship between serum klotho levels and thyroid hormones remains poorly understood. This study aimed to explore the correlation between serum klotho levels and thyroid hormones.

METHODS

Data was obtained from the NHANES cycles 2007-2008, 2009-2010, and 2011-2012. A total of 4674 participants were recruited for this study. Statistical analysis was using multiple linear regression analyses, and restricted cubic spline plots (RCS) to investigate the association between serum klotho levels and serum levels of thyroid hormones.

RESULTS

In the unadjusted covariate model, ln(klotho) significantly positively correlated with tT3, tT4, fT3, tT4/fT4, and tT3/fT3 (all P<0.01) and negatively correlated with TSH, tT4/tT3, and fT4/fT3 (all P<0.05). Furthermore, tT3, tT4, fT3and tT3/fT3 (P < 0.05) were still significant in the adjusted model. And it is worth noting that there is an approximately L-shaped nonlinear relationship between ln(klotho) and fT3,tT3 with a cut-off point of 6.697 (P-non-linear < 0.05). The stratification analysis showed gender and iodine level differences in the relationship between serum Klotho levels and thyroid hormones.

CONCLUSION

There is an L-shaped nonlinear relationship between ln(klotho) and fT3, tT3, suggesting that klotho could be involved in the physiological regulation of thyroid function.

Exercise-induced changes in plasma S-Klotho levels are associated with the obtained enhancements of heart rate variability in sedentary middle-aged adults: the FIT-AGEING study

The shed form of the Klotho protein (S-Klotho) is considered a biomarker of longevity, but it is still unknown whether the levels are related to heart rate (HR) and heart rate variability (HRV); both of them greatly influenced by the ageing process, physical fitness, exercise, and health status. This study aimed (i) to investigate the association between S-Klotho plasma levels with HR and HRV parameters and (ii) to examine the association of exercise-induced changes in S-Klotho and those obtained in HR and HRV parameters after a 12-week exercise intervention in sedentary middle-aged adults. Sixty-six sedentary middle-aged adults participated in this study (50% women; 45-65 years old). Participants were randomized into 4 groups: (a) a control group (no exercise), (b) a physical activity recommendation from the World Health Organization group, (c) a high-intensity interval training group, and (d) a high-intensity interval training group adding whole-body electromyostimulation. S-Klotho plasma levels, HR, and HRV parameters (SDNN, RMSSD, high frequency, stress score, and sympathetic/parasympathetic ratio) were measured. At baseline, S-Klotho plasma levels were not related to HR and HRV parameters. After the intervention, exercise-induced changes in S-Klotho plasma levels were positively associated with changes in SDNN (β=0.261; R2=0.102; p=0.014) and negatively related to changes in stress score and sympathetic/parasympathetic ratio (all β=-0.257; R2 ranges between 0.092 and 0.131; all p<0.020). Our study suggests that higher S-Klotho plasma levels are related to increased vagal influence and reduced sympathetic tone in the autonomic nervous system in sedentary middle-aged adults after different training programs. ClinicalTrials.gov identifier: CT03334357.

Serum β-klotho is a potential biomarker for the progression of hepatitis B virus-related liver diseases

INTRODUCTION

Hepatitis B virus (HBV) infection is a global epidemic that can lead to several liver diseases, seriously affecting people's health. This study aimed to investigate the clinical potential of serum β-klotho (KLB) as a promising biomarker in HBV-related liver diseases.

METHODOLOGY

This study enrolled 30 patients with chronic hepatitis B (CHB), 35 with HBV-related cirrhosis, 66 with HBV-related hepatocellular carcinoma (HCC), and 48 healthy individuals. ELISA measured the levels of serum KLB in the four groups. We then compared the differences in serum KLB levels among the groups and analyzed the relationship between serum KLB and routine clinical parameters.

RESULTS

The concentrations of serum KLB levels were increased sequentially among the healthy subjects, the HBV-related CHB group, the HBV-related cirrhosis group, and the HBV-related HCC group (p < 0.05). Expression of KLB was positively correlated with alpha-fetoprotein (AFP), total bilirubin, direct bilirubin, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl-transferase, alkaline phosphatase, total bile acid, serum markers for liver fibrosis, ascites, cirrhosis, splenomegaly, and model for end-stage liver disease sodium, while negatively correlated with platelet count, albumin, and prothrombin activity (p < 0.05). In addition, serum KLB has better sensitivity in diagnosing HCC than AFP, and serum KLB combined with AFP has higher sensitivity and specificity than AFP alone in diagnosing HCC.

CONCLUSIONS

Serum KLB level is associated with the severity of HBV-related liver diseases and has important diagnostic value for HCC. Therefore, it could be a predictive biomarker for monitoring disease progression.

Serum Klotho and insulin resistance: Insights from a cross-sectional analysis

The prevalence of diabetes has surged globally, posing significant health and economic burdens. Insulin resistance underlies the initiation and development of type 2 diabetes. Klotho is a crucial endogenous antiaging factor, associated with atherosclerotic cardiovascular diseases, cancer, neurological disorders, and renal diseases. It additionally has a function in controlling glucose metabolism and holds promise as a new therapeutic target for diabetes. However, its relationship with insulin resistance remains unclear. This study utilizes the National Health and Nutrition Examination Survey (NHANES) 2007 to 2016 data to investigate the relationship between serum Klotho concentrations and insulin resistance. In this observational study, information from the NHANES spanning 2007 to 2016 was employed. The sample consisted of 6371 participants. Weighted linear regression model and chi-square tests were utilized to assess differences in continuous and categorical variables, respectively, among groups categorized by Klotho quartiles. The relationship between Klotho and HOMA-IR (homeostatic model assessment of insulin resistance) was studied using multiple linear regression. Smooth curve fitting was used to analyze nonlinear relationships and the inflection point was determined through a 2-stage linear regression method. After adjusting for multiple confounding factors, serum Klotho levels were found to be positively correlated with insulin resistance [0.90 (0.68, 1.13)]. This correlation is nonlinear and exhibits a saturation effect, with the inflection point identified at 1.24 pg/µL. When Klotho levels are below 1.24 pg/µL, for every unit increase in Klotho, HOMA-IR increases by 1.30 units. Conversely, when Klotho levels exceed 1.24 pg/µL, there is no correlation between HOMA-IR and Klotho. Subgroup analysis reveals that the relationship between HOMA-IR and Klotho varies depending on diabetes and body mass index (BMI). This positive correlation was most prominent in the obese nondiabetic population. There is a positive correlation between serum Klotho and insulin resistance.

Analysis of the relationship between mild cognitive impairment and serum klotho protein and insulin-like growth factor-1 in the elderly

BACKGROUND

Mild cognitive impairment (MCI) is a mild memory or cognitive impairment.

OBJECTIVE

To explore the relationship between serum klotho (K1) protein and insulin-like growth factor-1 and mild cognitive impairment in the elderly in order to provide accurate and appropriate indicators for clinical diagnosis and treatment of MCI.

METHODS

This randomized stratified study adopted a multistage cluster sampling method. 161 elderly patients with mild cognitive impairment were included as the MCI group, and 161 healthy people matched with the MCI group in gender, age and education were selected as the control group.

RESULTS

The levels of serum K1 protein and insulin-like growth factor-1 in the MCI group were lower than those in the control group (P< 0.05). Both IGF-1 and K1 had predictive value for MCI (P< 0.05). The area under the curve (AUC) of IGF-1 for predicting MCI was 0.859 (95% CI: 0.790∼0.929), and the AUC of K1 for predicting MCI was 0.793 (95% CI: 0.694∼0.892). The value of joint prediction of the two indicators was the highest, with an AUC of 0.939 (95% CI: 0.896-0.993).

CONCLUSION

High serum K1 and insulin-like growth factor-1 are the protective factors of cognitive impairment in MCI patients. Both IGF-1 and serum K1 proteins have predictive value for MCI, and the combination of the two indicators has the highest predictive value.

Association of bone biomarkers with advanced atherosclerotic disease in people with overweight/obesity

BACKGROUND

A growing body of evidence suggests a potential link between bone metabolism and cardiovascular disease. Aim of this study was to investigate the relationship between levels of circulating bone turnover biomarkers and advanced atherosclerosis.

METHODS

Klotho (KL), sclerostin (SOST), osteopontin (OPN) and osteoprotegerin (OPG) were measured in patients undergoing elective coronary angiography and carotid Doppler ultrasound. The primary outcome was the difference in bone biomarkers levels between participants with and without advanced atherosclerosis, defined as the presence of a critical coronary (≥70%) and/or carotid (≥50%) stenosis.

RESULTS

A total of 80 subjects (32.5% females) with a mean age of 68 ± 10 years were included. Advanced atherosclerosis was detected in 55 (68.8%) patients. Subjects with advanced atherosclerosis showed higher serum levels of OPG (p = 0.0015) and SOST (p = 0.017) and similar levels of KL (p = 0.62) and OPN (p = 0.06) compared to patients without. After adjustment for age and sex, only elevated levels of OPG remained significantly associated with advanced atherosclerosis (p = 0.011).

CONCLUSIONS

Higher serum levels of OPG are independently associated with advanced atherosclerosis confirming a common bond between bone metabolism and vascular disease. Further investigations on the role of selected bone biomarkers in the pathogenesis of cardiovascular disease are needed.

Circulating α-klotho regulates metabolism via distinct central and peripheral mechanisms

Emerging evidence implicates the circulating α-klotho protein as a prominent regulator of energy balance and substrate metabolism, with diverse, tissue-specific functions. Despite its well-documented ubiquitous role inhibiting insulin signaling, α-klotho elicits potent antidiabetic and anti-obesogenic effects. α-Klotho facilitates insulin release and promotes β cell health in the pancreas, stimulates lipid oxidation in liver and adipose tissue, attenuates hepatic gluconeogenesis, and increases whole-body energy expenditure. The mechanisms underlying α-klotho's peripheral functions are multifaceted, including hydrolyzing transient receptor potential channels, stimulating integrin β1➔focal adhesion kinase signaling, and activating PPARα via inhibition of insulin-like growth factor receptor 1. Moreover, until recently, potential metabolic roles of α-klotho in the central nervous system remained unexplored; however, a novel α-klotho➔fibroblast growth factor receptor➔PI3kinase signaling axis in the arcuate nucleus of the hypothalamus has been identified as a critical regulator of energy balance and glucose metabolism. Overall, the role of circulating α-klotho in the regulation of metabolism is a new focus of research, but accumulating evidence identifies this protein as an encouraging therapeutic target for Type 1 and 2 Diabetes and obesity. This review analyzes the new literature investigating α-klotho-mediated regulation of metabolism and proposes impactful future directions to progress our understanding of this complex metabolic protein.

Associations of serum soluble klotho and fibroblast growth factor 23 with carotid artery calcification in patients undergoing continuous ambulatory peritoneal dialysis: A retrospective study

ABSTRACT

This study aimed to assess the associations of serum soluble klotho and fibroblast growth factor 23 (FGF-23) with the occurrence of carotid artery calcification. Peritoneal dialysis patients treated from June 2018 to June 2019 were retrospectively analyzed. They were divided into the carotid artery calcification and non-carotid artery calcification groups according to color Doppler ultrasound findings. Basic indicators in both groups were compared, and the influencing factors of carotid artery calcification were analyzed by logistic regression. Among the 73 continuous ambulatory peritoneal dialysis (CAPD) patients enrolled, 40 (54.8%) had carotid artery calcification. Significant differences were found in age (68.85 ± 7.45 vs 46.62 ± 5.51 years), dialysis time (8.15 ± 1.42 vs 6.02 ± 1.14 months), klotho amounts (325.56 ± 41.15 vs 436.65 ± 45.58 pg/mL) and FGF-23 levels (114.45 ± 15.56 vs 70.15 ± 12.23 pg/mL) between the carotid artery calcification and non-carotid artery calcification groups (all P < .001). The above factors were associated with carotid artery calcification occurrence in univariate analysis. Multivariate analysis showed that elevated age (odds ratio [OR] = 1.55, 95% confidence interval [CI] 1.13-1.74; P = .025) and FGF-23 (OR = 2.16, 95% CI 2.01-2.44; P = .042), and lower klotho (OR = 0.66, 95% CI 0.47-0.85; P = .036) were independent risk factors for carotid artery calcification in CAPD. Serum FGF-23 and age are risk factors for carotid artery calcification in patients with CAPD, whereas klotho is a protective factor.

Soluble Alpha Klotho in Acromegaly: Comparison With Traditional Markers of Disease Activity

CONTEXT

Soluble alpha klotho (sαKL) has been linked to growth hormone (GH) action, but systematic evaluation and comparisons with traditional biomarkers in acromegaly are lacking.

OBJECTIVE

To evaluate the potential of sαKL to aid classification of disease activity.

METHODS

This retrospective study at 2 academic centers included acromegaly patients before surgery (A, n = 29); after surgery (controlled, discordant, or uncontrolled) without (B1, B2, B3, n = 28, 11, 8); or with somatostatin analogue treatment (C1, C2, C3, n = 17, 11, 5); nonfunctioning pituitary adenomas (n = 20); and healthy controls (n = 31). sαKL was measured by immunoassay and compared with traditional biomarkers (random and nadir GH, insulin-like growth factor I [IGF-I], IGF binding protein 3). Associations with disease activity were assessed.

RESULTS

sαKL was correlated to traditional biomarkers, particularly IGF-I (rs=0.80, P <0.0001). High concentrations before treatment (A, median, interquartile range: 4.04 × upper limit of normal [2.26-8.08]) dropped to normal after treatment in controlled and in most discordant patients. A cutoff of 1548 pg/mL for sαKL discriminated controlled (B1, C1) and uncontrolled (B3, C3) patients with 97.8% (88.4%-99.9%) sensitivity and 100% (77.1%-100%) specificity. sαKL was below the cutoff in 84% of the discordant subjects. In the remaining 16%, elevated sαKL and IGF-I persisted, despite normal random GH. Sex, age, body mass index, and markers of bone and calcium metabolism did not significantly affect sαKL concentrations.

CONCLUSION

Our data support sαKL as a biomarker to assess disease activity in acromegaly. sαKL exhibits close association with GH secretory status, large dynamic range, and robustness toward biological confounders. Its measurement could be helpful particularly when GH and IGF-I provide discrepant information.

Effect of Lipopolysaccharide-Induced Inflammatory Challenge on β-Glucuronidase Activity and the Concentration of Quercetin and Its Metabolites in the Choroid Plexus, Blood Plasma and Cerebrospinal Fluid

Quercetin-3-glucuronide (Q3GA), the main phase II metabolite of quercetin (Q) in human plasma, is considered to be a more stable form of Q for transport with the bloodstream to tissues, where it can be potentially deconjugated by β-glucuronidase (β-Gluc) to Q aglycone, which easily enters the brain. This study evaluates the effect of lipopolysaccharide (LPS)-induced acute inflammation on β-Gluc gene expression in the choroid plexus (ChP) and its activity in blood plasma, ChP and cerebrospinal fluid (CSF), and the concentration of Q and its phase II metabolites in blood plasma and CSF. Studies were performed on saline- and LPS-treated adult ewes (n = 40) receiving Q3GA intravenously (n = 16) and on primary rat ChP epithelial cells and human ChP epithelial papilloma cells. We observed that acute inflammation stimulated β-Gluc activity in the ChP and blood plasma, but not in ChP epithelial cells and CSF, and did not affect Q and its phase II metabolite concentrations in plasma and CSF, except Q3GA, for which the plasma concentration was higher 30 min after administration (p < 0.05) in LPS- compared to saline-treated ewes. The lack of Q3GA deconjugation in the ChP observed under physiological and acute inflammatory conditions, however, does not exclude its possible role in the course of neurodegenerative diseases.

Low serum klotho concentration is associated with worse cognition, psychological components of frailty, dependence, and falls in nursing home residents

Serum alpha-klotho (s-klotho) protein has been linked with lifespan, and low concentrations of s-klotho have been associated with worse physical and cognitive outcomes. Although its significance in aging remains unclear, s-klotho has been proposed as a molecular biomarker of frailty and dependence. This study is a secondary analysis of data from a clinical trial performed in a population of 103 older individuals living in 10 nursing homes in Gipuzkoa (Spain). We aimed to elucidate associations between s-klotho (as measured by enzyme-linked immunosorbent assay) and body composition, physical fitness, and cognition, as well as frailty and dependence (determined using validated tests and scales). In addition, we investigated the association of s-klotho concentration with falls in the six months following the initial assessment. Low s-klotho levels were associated with a lower score in the psychological component of the Tilburg Frailty Indicator, a worse score in the Coding Wechsler Adult Intelligence Scale, and a greater dependence in activities of daily living. Moreover, participants with lower s-klotho concentrations suffered more falls during the 6 months after the assessment. Future translational research should aim to validate klotho's putative role as a biomarker that could identify the risk of aging-related adverse events in clinical practice.

Blood Flow Restriction Training Blunts Chronic Kidney Disease Progression in Humans

PURPOSE

This study aimed to verify the effect of 6 months of periodized resistance training (RT) with and without blood flow restriction (BFR) in patients with stage 2 chronic kidney disease (CKD) on glomerular filtration rate (GFR), uremic parameters, cytokines, and klotho-fibroblast growth factor 23 (FGF23) axis.

METHODS

A total of 105 subjects were randomized in three groups of 35 each: control (CTL), RT, and RT + BFR. A first visit was required for an anamnesis to evaluate the number of medications and anthropometric measurements (body weight, height, and body mass index). Muscle strength (one-repetition maximum) was assessed. Venous blood samples were collected at baseline and after 6 months of training in all patients for the analysis of markers of renal function and integrity, as well as for the determination of the inflammatory profile. Statistical significances were adopted with P < 0.05.

RESULTS

Both training therapies attenuated the decline of GFR (P < 0.05). The majority of CTL patients declined to stage 3 CKD (88.5%), whereas fewer incidents were noted with RT (25.7%) and RT + BFR (17.1%). Improved uremic parameters as well as inflammation (IL-6, IL-10, IL-15, IL-17a, IL-18, and TNF-α) and klotho-FGF23 axis in RT and RT + BFR (P < 0.05) were observed. Monocyte chemoattractant protein 1 was not changed (P > 0.05) but presented a large effect size (Cohen's d), demonstrating a propensity for improvement.

CONCLUSION

Six months of periodized RT with and without BFR in patients with stage 2 CKD attenuated the progression of the disease by maintaining GFR, improving uremic parameters, cytokine profile regulation, and klotho-FGF23 axis.

A novel antibody for the detection of alternatively spliced secreted KLOTHO isoform in human plasma

αKlotho is primarily known to express as a transmembrane protein. Proteolytic cleavage results in shedding of the extracellular domain which enters systemic circulation. A truncated form of αKlotho resulting from alternative splicing of the αKLOTHO transcript exists and is believed to be secreted, thereby also entering systemic circulation. Existing ELISA methods fail to distinguish between the two circulating isoforms resulting in inconsistencies in assessing circulating αKlotho levels. We have exploited a unique 15aa peptide sequence present in the alternatively spliced secreted isoform to generate an antibody and show that it is able to specifically detect only the secreted Klotho isoform in human plasma. This finding will facilitate in distinguishing the levels of different circulating Klotho isoforms in health and disease and enhance their potential to serve as a biomarker for CKD and other conditions.

Low levels of circulating anti-ageing hormone Klotho predict the onset and progression of diabetic retinopathy

BACKGROUND

Klotho is a circulating anti-ageing hormone that predicts progression of cardiovascular and renal disease. The role of Klotho in diabetic retinopathy is unknown.

METHODS

We performed a single-centre observational study of 81 people (males 62%) with type 2 diabetes followed for a median of 44 months. Circulating levels of Klotho and other markers, were measured from stored samples. The primary outcome was progression of retinopathy defined as new onset retinopathy or step change in retinopathy grading.

RESULTS

During follow-up, 46 (57%) people reached the primary outcome. People with progression of retinopathy had lower levels of serum Klotho as compared to those without (median (interquartile range) 226.9 (171.1-394.0) vs 484.5 (221.8-709.9) pg/ml, p = 0.001). In multivariable logistic regression analyses, baseline Klotho level was the only variable independently associated with reduced risk of progression of retinopathy. Our results suggest that a halving of circulating Klotho levels increases the risk of retinopathy progression by 44%.

CONCLUSION

In people with type 2 diabetes, lower circulating levels of the vascular protective hormone Klotho are associated with increased risk of progression of diabetic retinopathy. Klotho may be a novel biomarker and potential treatment target for diabetic eye disease.

Increased Plasma Heparanase Activity in COVID-19 Patients

Reports suggest a role of endothelial dysfunction and loss of endothelial barrier function in COVID-19. It is well established that the endothelial glycocalyx-degrading enzyme heparanase contributes to vascular leakage and inflammation. Low molecular weight heparins (LMWH) serve as an inhibitor of heparanase. We hypothesize that heparanase contributes to the pathogenesis of COVID-19, and that heparanase may be inhibited by LMWH. To test this hypothesis, heparanase activity and heparan sulfate levels were measured in plasma of healthy controls (n = 10) and COVID-19 patients (n = 48). Plasma heparanase activity and heparan sulfate levels were significantly elevated in COVID-19 patients. Heparanase activity was associated with disease severity including the need for intensive care, lactate dehydrogenase levels, and creatinine levels. Use of prophylactic LMWH in non-ICU patients was associated with a reduced heparanase activity. Since there is no other clinically applied heparanase inhibitor currently available, therapeutic treatment of COVID-19 patients with low molecular weight heparins should be explored.

Mediation of the relationship between proteinuria and serum phosphate: Insight from the KNOW-CKD study

Proteinuria and hyperphosphatemia are risk factors for cardiovascular disease in patients with chronic kidney disease (CKD). Although the interaction between proteinuria and the serum phosphate level is well established, the mechanistic link between the two, particularly the extent to which this interaction is mediated by phosphate-regulating factors, remains poorly understood. In this study, we examined the association between proteinuria and the serum phosphate level, as well as potential mediators, including circulating fibroblast growth factor (FGF23)/klotho, the 24-h urinary phosphate excretion rate to glomerular filtration rate ratio (EP/GFR), and the 24-h tubular phosphate reabsorption rate to GFR ratio (TRP/GFR). The analyses were performed with data from 1793 patients in whom 24-h urine protein and phosphate, serum phosphate, FGF23, and klotho levels were measured simultaneously, obtained from the KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD). Multivariable linear regression and mediation analyses were performed. Total, direct, and indirect effects were also estimated. Patients with high serum phosphate levels were found to be more likely to exhibit greater proteinuria, higher FGF23 levels, and lower klotho levels. The 24-h EP/GFR increased and the 24-h TRP/GFR decreased with increasing proteinuria and CKD progression. Simple mediation analyses showed that 15.4% and 67.9% of the relationship between proteinuria and the serum phosphate level were mediated by the FGF23/klotho ratio and 24-h EP/GFR, respectively. Together, these two factors accounted for 73.1% of the relationship between serum markers. These findings suggest that proteinuria increases the 24-h EP/GFR via the FGF23/klotho axis as a compensatory mechanism for the increased phosphate burden well before the reduction in renal function is first seen.

Vestronidase alfa: Recombinant human β-glucuronidase as an enzyme replacement therapy for MPS VII

Mucopolysaccharidosis VII (MPS VII) is a rare lysosomal storage disease characterized by a deficiency in the enzyme β-glucuronidase that has previously been successfully treated in a mouse model with enzyme replacement therapy. Here, we present the generation of a novel, highly sialylated version of recombinant human β-glucuronidase (rhGUS), vestronidase alfa, that has high uptake, resulting in an improved enzyme replacement therapy for the treatment of patients with MPS VII. In vitro, vestronidase alfa has 10-fold more sialic acid per mole of rhGUS monomer than a prior rhGUS version (referred to as GUS 43/44) and demonstrated very high affinity at ~1 nM half maximal uptake in human MPS VII fibroblasts. Vestronidase alfa has a longer enzymatic half-life after uptake into fibroblasts compared with other enzymes used as replacement therapy for MPS (40 days vs 3 to 4 days, respectively). In pharmacokinetic and tissue distribution experiments in Sprague-Dawley rats, intravenous administration of vestronidase alfa resulted in higher serum rhGUS levels and enhanced β-glucuronidase activity distributed to target tissues. Weekly intravenous injections of vestronidase alfa (0.1 mg/kg to 20 mg/kg) in a murine model of MPS VII demonstrated efficient enzyme delivery to all tissues, including bone and brain, as well as reduced lysosomal storage of glycosaminoglycans (GAGs) in a dose-dependent manner, resulting in increased survival after 8 weeks of treatment. Vestronidase alfa was well-tolerated and demonstrated no toxicity at concentrations that reached 5-times the proposed clinical dose. In a first-in-human phase 1/2 clinical trial, a dose-dependent reduction in urine GAG levels was sustained over 38 weeks of treatment with vestronidase alfa. Together, these results support the therapeutic potential of vestronidase alfa as an enzyme replacement therapy for patients with MPS VII.

FGF23-Related Hypophosphataemic Bone Disease

Metabolic skeletal dysplasias comprise an extensive group of diseases capable of causing changes, usually progressive, in the bone and are due to hereditary disorders in many cases. The diagnosis and treatment of these diseases are not without difficulty, both because of their rarity and their possible confusion with more common diseases. A paradigmatic case of these metabolic skeletal dysplasias is X-linked hypophosphataemic rickets, which causes phosphaturia, a condition that alters the phosphate-calcium metabolism balance consequently causing, among other conditions, skeletal deformities and short stature. The genetic advances in recent years allow a much more accurate diagnosis of this disease when suspected, making differential diagnosis easier with similar entities but whose real causes are different. A better understanding of the phosphate-calcium metabolism allows us to replace the symptomatic treatment currently available with one that involves rebalancing the excess of fibroblast growth factor 23 (FGF23) by using monoclonal antibodies. In November 2018, a symposium sponsored by Kyowa Kirin Pharmaceuticals took place in Madrid, in which national and international experts addressed several aspects of these rare kidney diseases. Some topics addressed were the present and future genetic diagnosis, the use of multi-gene panels in renal or skeletal diseases, the role of animal models to better understand underlying skeletal changes, and the role of conventional radiology and surgery in the diagnosis and final treatment of bone deformities; all these without forgetting the important role of FGF23 and Klotho imbalances that result in the genetic change causing this disease. The optimization and limitations of conventional treatments currently available was also a topic addressed extensively, as well as the implications that new treatments against FGF23 could have in the future. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by the author.

Fibroblast growth factor 23 and 25(OH)D levels are related to abdominal obesity and cardiovascular risk in patients with polycystic ovarian syndrome

Fibroblast growth factor 23 (FGF23) and Klotho are extensively studied in relation to bone metabolism and progression of chronic kidney disease. There is very limited information about their role in polycystic ovarian syndrome (PCOS). The aim of the present study was to investigate some bone markers in women with PCOS in relation to obesity and cardiovascular risk. In the study were included 80 patients, divided into three age-matched groups -Non-obese PCOS (n = 40); Obese PCOS (n = 20) and Obese control group (n = 20). Bone marker levels were measured by an enzyme-linked immunosorbent assay. Obese PCOS patients had higher levels of FGF23 and sRANKL, lower levels of 25(OH)D and higher prevalence of vitamin D deficiency compared to non-obese subjects. Patients with abdominal obesity (waist circumference >80 cm) independently of PCOS status had significantly higher levels of FGF23 (112.5 ± 86.5 vs. 73.4 ± 37.9 pg/ml; p = .023) and lower of 25(OH)D (35.8 ± 21.4 vs 47.8 ± 26.5 nmol/l; p = .034). Patients with PCOS at risk of cardiovascular diseases according to AE-PCOS consensus also had increased levels of FGF23 (111.6 ± 84.5 vs. 66.5 ± 35.1 pg/ml; p = .031) and decreased levels of 25(OH)D (31.9 ± 16.8 vs. 47.1 vs 28.4 nmol/l; p = .017) compared to those not at risk. There was no correlation between bone markers and blood glucose levels, insulin resistance or hormonal levels.

Clinical Potential of Targeting Fibroblast Growth Factor-23 and αKlotho in the Treatment of Uremic Cardiomyopathy

Chronic kidney disease is highly prevalent, affecting 10% to 15% of the adult population worldwide and is associated with increased cardiovascular morbidity and mortality. As chronic kidney disease worsens, a unique cardiovascular phenotype develops characterized by heart muscle disease, increased arterial stiffness, atherosclerosis, and hypertension. Cardiovascular risk is multifaceted, but most cardiovascular deaths in patients with advanced chronic kidney disease are caused by heart failure and sudden cardiac death. While the exact drivers of these deaths are unknown, they are believed to be caused by uremic cardiomyopathy: a specific pattern of myocardial hypertrophy, fibrosis, with both diastolic and systolic dysfunction. Although the pathogenesis of uremic cardiomyopathy is likely to be multifactorial, accumulating evidence suggests increased production of fibroblast growth factor-23 and αKlotho deficiency as potential major drivers of cardiac remodeling in patients with uremic cardiomyopathy. In this article we review the increasing understanding of the physiology and clinical aspects of uremic cardiomyopathy and the rapidly increasing knowledge of the biology of both fibroblast growth factor-23 and αKlotho. Finally, we discuss how dissection of these pathological processes is aiding the development of therapeutic options, including small molecules and antibodies, directly aimed at improving the cardiovascular outcomes of patients with chronic kidney disease and end-stage renal disease.

Biomarkers of vascular disease in diabetes: the adipose-immune system cross talk

Experimental and clinical studies aimed at investigating the mechanism(s) underlying vascular complications of diabetes indicate that a great number of molecules are involved in the pathogenesis of these complications. Most of these molecules are inflammatory mediators or markers generated by immune or adipose tissue. Some of them, i.e. resistin and sortilin, have been shown to be involved in the cross talk between adipocytes and inflammatory cells. This interaction is an attractive area of research, particularly in type 2 diabetes and obesity. Other proteins, such as adiponectin and visfatin, appear to be more promising as possible vascular markers. In addition, some molecules involved in calcium/phosphorus metabolism, such as klotho and FGF23, have an involvement in the pathogenesis of diabetic vasculopathy, which appears to be dependent on the degree of vascular impairment. Inflammatory markers are a promising tool for treatment decisions while measuring plasma levels of adipokines, sortilin, Klotho and FGF23 in adequately sized longitudinal studies is expected to allow a more precise characterization of diabetic vascular disease and the optimal use of personalized treatment strategies.

Parathyroid Hormone and Plasma Phosphate Are Predictors of Soluble α-Klotho Levels in Adults of European Descent

CONTEXT

α-klotho is an integral membrane protein that serves as a coreceptor for fibroblast growth factor 23 (FGF23) in conjunction with cognate fibroblast growth factor receptors. Proteolytic cleavage sheds the ectodomain of α-klotho (soluble α-klotho) as an endocrine substance into blood, urine, and cerebrospinal fluid.

OBJECTIVE

To study the relationship of soluble α-klotho to mineral metabolism in the general population with mainly preserved kidney function.

DESIGN

Cross-sectional analysis of the associations between soluble α-klotho with laboratory markers of markers of mineral metabolism in a population-based cohort.

SETTING

Three centers in Switzerland including 1128 participants.

MEASURES

Soluble full-length α-klotho levels by a specific immunoassay and markers of mineral metabolism.

RESULTS

The median serum level of soluble α-klotho was 15.0 pmol/L. Multivariable analyses using α-klotho as the outcome variable revealed a sex-by-PTH interaction: In men, PTH was positively associated with α-klotho levels, whereas this association was negative in women. Plasma phosphate associated with soluble α-klotho levels in an age-dependent manner, changing from a positive association in young adults gradually to a negative association in the elderly. The decline of 1,25 (OH)2 vitamin D3 levels in parallel to the gradual impairment of kidney function was greatly attenuated in the setting of high circulating soluble α-klotho levels.

CONCLUSIONS

Soluble α-klotho level is associated with plasma phosphate in an age-dependent manner and with PTH in a sex-dependent manner. Furthermore, our data reveal soluble α-klotho as a modulator of 1,25 (OH)2 vitamin D3 levels in individuals with preserved renal function.

Fibroblast Growth Factor 23 (FGF23) and Klotho Protein in Beta-Thalassemia

Derangements in phosphate and calcium homeostasis are common in patients with beta-thalassemia. Fibroblast growth factor 23 (FGF23) is among the main hormones regulating phosphate levels, while several studies underline an interplay between iron (Fe) and FGF23. Herein, we investigated, for the first time, the serum intact molecule (iFGF23) and the carboxyl-terminal fragment (C-FGF23) and Klotho levels simultaneously in patients with beta-thalassemia major receiving iron chelation regimens in comparison to healthy control subjects. We also correlated them with the body iron burden. The observational case-control study included 81 subjects (40 thalassemic patients and 41 healthy controls). Serum iFGF23, C-FGF23 and Κlotho were measured by ELISA. Parathormone, 25-hydroxycholecalciferol, calcium, and phosphorus were measured in blood and/or urine. The degree of hemosiderosis was evaluated by assessing the serum ferritin levels and performing T2* MRI measurements. Serum C-FGF23 levels were significantly lower in patients compared to control subjects (p=0.04), while iFGF23 and Klotho levels did not differ. Serum C-FGF23 levels were negatively correlated with ferritin (r=-0,421, p=0.018), whereas there were no significant correlations of each of the three factors with the iron chelation therapy. Decreased serum C-FGF23 levels were found in βTh patients which may be attributed to inhibition of proteolytic cleavage of iFGF23. Further studies in a greater number of patients will shed more light on the disturbances of the iFGF23, Klotho and C-FGF23 in thalassemia and their possible role in bone disease of such patients.

INCREASED SYSTEMIC HEPARANASE IN RETINAL VEIN OCCLUSION IS ASSOCIATED WITH ACTIVATION OF INFLAMMATION AND THROMBOPHILIA

PURPOSE

To investigate the levels of systemic heparanase, inflammatory markers, and coagulation factor activities in patients with retinal vein occlusion (RVO).

METHODS

This prospective study included 18 patients with central RVO, 22 patients with branch RVO, and 40 patients with age-related cataract as the control group. Serum heparanase protein levels and activities were measured by ELISA and a heparan degrading enzyme assay kit, respectively. Serum levels of MMP-2, MMP-9, TLR-2, and TLR-4 were measured by ELISA kits. The activities of coagulation factors (V, VII, VIII, and IX) were determined with an autoanalyzer. The Mann-Whitney U test was used to compare the above parameters between patients with RVO and control subjects. The relationship between two of the above parameters was analyzed by Spearman's correlation.

RESULTS

Patients with RVO had higher levels of systemic heparanase protein, heparanase activities, coagulation factors' (V, VIII, and IX) activities, MMP-2, MMP-9, TLR-2, and TLR-4 compared with the control group. Systemic heparanase levels were correlated with serum levels of MMP-2, MMP-9, TLR-2, TLR-4, and activities of coagulation factors VIII and IX.

CONCLUSION

Increase of systemic heparanase in RVO is associated with activation of systemic inflammation and blood hypercoagulability.

FGF23-klotho axis as predictive factors of fractures in type 2 diabetics with early chronic kidney disease

BACKGROUND

The aim of our study was to evaluate the relevance of FGF23-klotho axis in the predisposition for bone fractures in type 2 diabetic patients with early chronic kidney disease.

METHODS

In a prospective study we included 126 type 2 diabetic patients with CKD stages 2-3 (from 2010 to 2017). We used descriptive statistics, ANOVA and chi-square test. Our population was divided into two groups according to the occurrence of a bone fracture event or not, and the groups were compared considering several biological and laboratorial parameters. We employed a multiple regression model to identify risk factors for bone fracture events and hazard ratios (HR) were calculated using a backward stepwise likelihood ratio (LR) Cox regression.

RESULTS

Patients with a fracture event displayed higher levels of FGF-23, Phosphorus, PTH, TNF-α, OxLDL, HOMA-IR, calcium × phosphorus product and ACR and lower levels of Osteocalcin, α-Klotho, 25(OH)D3 and eGFR compared with patients without a fracture event (p < 0.001). The number of patients with a fracture event was higher than expected within inclining CKD stages (χ2, p = 0.06). The occurrence of fracture and the levels of TNF- α, klotho, 25(OH)D3 and OxLDL were found to predict patient entry into RRT (p < 0.05). Age, osteocalcin, α-Klotho and FGF-23 independently influenced the occurrence of bone fracture (p < 0.05).

CONCLUSIONS

α-Klotho and FGF-23 levels may have a good clinical use as biomarkers to predict the occurrence of fracture events.

FGF23-Klotho axis in patients with rheumatoid arthritis

OBJECTIVES

We aimed to compare serum Klotho and fibroblast growth factor-23 (FGF-23) levels between rheumatoid arthritis (RA) patients and healthy controls. Possible association between FGF-23 and soluble Klotho with different characteristic of the disease as well as their potential role as surrogate markers of cardiovascular disease (CVD) were studied.

METHODS

Sixty-three patients with RA recruited at Vega-Baja Hospital, Orihuela (Spain) from November 2016 to May 2018 and sixty-five age- and sex-matched healthy controls were included in this study. Serum Klotho and FGF-23 were analysed using ELISA.

RESULTS

Patients had higher serum levels of Klotho than healthy controls (p˂0.0001). They were positively associated with the presence of anticitrullinated peptide antibody and rheumatic factor (p<0.05). Klotho serum levels were higher in RA patients treated with biologic agents than in those undergoing conventional therapy (p=0.008). However, no association with carotid intima media thickness was found. Although no significant differences in serum FGF-23 levels between patients and controls were found (p=0.43), FGF-23 levels were positively associated with low-density lipoprotein (LDL-c) level (p<0.05) and smoking (p=0.008) in patients with RA.

CONCLUSIONS

The increased serum Klotho levels in RA patients, especially in those undergoing biologic therapy, may indicate a potential implication in the pathogenesis of the disease. Although levels of FGF-23 were related to LDL-c levels, the FGF-23-Klotho axis does not seem to be related to subclinical arteriosclerosis in RA.

Investigating subtle kidney injury in primary hyperparathyroidism by means of sensitive and specific biomarkers

OBJECTIVE

Kidney involvement is a common complication in primary hyperparathyroidism (PHPT). No study so far has assessed the prevalence of kidney injury developing before the reduction in glomerular filtration rate (GFR) in PHPT. The study was aimed at establishing the potential role of biomarkers of kidney injury in detecting subtle renal damage in patients with PHPT.

DESIGN

Cross-sectional study.

PATIENTS

A total of 69 postmenopausal patients with PHPT and 41 healthy age- and sex-matched subjects were studied. Exclusion criteria were as follows: GFR < 30 mL/min, chronic inflammatory disease, nephrotic syndrome, infection, malignancy, heart failure, recent exposure to iodinated contrast media or nonsteroidal anti-inflammatory drugs.

MEASUREMENTS

We measured a panel of sensitive biomarkers of kidney injury in PHPT vs controls.

RESULTS

Mean FGF23 and Klotho were higher in PHPT (72 ± 48 and 811 ± 366 pg/mL, respectively) than controls (53 ± 23.5 and 668.6 ± 17; P < .02 and P < .05). Urine KIM-1/uCr was significantly higher in PHPT (1.4^-6  ± 1.3^-6 ) than controls (9.2^-7  ± 7^-7 ; P < .05); this was particularly evident in the CrCl 60-89 mL/min category (1.3⁶  ± 9⁷ vs 8.2^-7  ± 3.6^-7 ; P < .02). Mean values of urine NGAL/uCr were higher in PHPT with (n = 28) compared to those without kidney stones (n = 35; 1.8^-5  ± 1.4^-5 and 1^-5  ± 8^-6 ; P < .0001). We found significant positive associations between urine NGAL/uCr and Ca (R = .292, P < .02) and urine KIM1/uCr and PTH (R = .329, P < .01).

CONCLUSIONS

We propose the utilization of these molecules, particularly urine KIM-1/uCr and urine NGAL/uCr ratios for the assessment of subtle kidney injury in patients with PHPT. These molecules are elevated in tubular necrosis and have potential role in the development of kidney damage in PHPT, according to the severity of the disease.

First Report of a Patient with MPS Type VII, Due to Novel Mutations in GUSB, Who Underwent Enzyme Replacement and Then Hematopoietic Stem Cell Transplantation

We report the case of a boy who was diagnosed with mucopolysaccharidosis (MPS) VII at two weeks of age. He harbored three missense β-glucuronidase (GUSB) variations in exon 3: two novel, c.422A>C and c.424C>T, inherited from his mother, and the rather common c.526C>T, inherited from his father. Expression of these variations in transfected HEK293T cells demonstrated that the double mutation c.422A>C;424C>T reduces β-glucuronidase enzyme activity. Enzyme replacement therapy (ERT), using UX003 (vestronidase alfa), was started at four months of age, followed by a hematopoietic stem cell allograft transplantation (HSCT) at 13 months of age. ERT was well tolerated and attenuated visceromegaly and skin infiltration. After a severe skin and gut graft-versus-host disease, ERT was stopped six months after HSCT. The last follow-up examination (at the age of four years) revealed a normal psychomotor development, stabilized growth curve, no hepatosplenomegaly, and no other organ involvement. Intriguingly, enzyme activity had normalized in leukocytes but remained low in plasma. This case report illustrates: (i) The need for an early diagnosis of MPS, and (ii) the possible benefit of a very early enzymatic and/or cellular therapy in this rare form of lysosomal storage disease.

Resveratrol and 1,25-dihydroxyvitamin D co-administration protects the heart against D-galactose-induced aging in rats: evaluation of serum and cardiac levels of klotho

The current study investigates the cooperative cardioprotective effect of calcitriol (active form of vitamin D) combined with resveratrol in a rat model of D-galactose (D.gal)-induced aging. Male Wistar rats received resveratrol (D.gal + Res), calcitriol (D.gal + Cal), or a combination of them (D.gal + Res + Cal). Intact animals served as control (Ctl). Blood pressure (BP) was recorded by cannulation of the left carotid artery. Fibrosis and cell size were assessed by Masson's trichrome and hematoxylin-eosin staining, respectively. Cardiac and serum level of antiaging protein, klotho, was measured by ELISA assay method. Gene expression was evaluated by real-time RT-PCR. Biochemical tests were performed according to the standardized method. In D.gal + Res + Cal group, BP, heart weight-to-body weight ratio, and cardiomyocytes size decreased significantly compared with D-gal group. The cardiac transcription levels of catalase and superoxide dismutase 1 and 2 were upregulated in D.gal + Res + Cal compared to the D.gal group (P < 0.001, P < 0.05, P < 0.05, respectively). Increased level of malondialdehyde was observed in D.gal group (P < 0.01 vs. Ctl) which was normalized partially in D.gal + Res + Cal group (P < 0.05). Catalase and superoxide dismutase activity also increased in D.gal + Res + Cal group (P < 0.01 vs. D.gal). Cardiac Klotho, as the antiaging protein, remained unchanged at mRNA and protein levels among the experimental groups. The serum level of Klotho did not change significantly in D.gal group; however, in D.gal + Res + Cal group, serum klotho concentration was increased (P < 0.05 vs. D.gal). It could be concluded that co-administration of resveratrol and vitamin D protects the heart against aging-induced damage by the modulation of hemodynamic parameters and antioxidant status of the heart. Furthermore, increased serum level of klotho could be a novel mechanism for antiaging effects of resveratrol and vitamin D.

Klotho restrain RIG-1/NF-κB signaling activation and monocyte inflammatory factor release under uremic condition

AIMS

Systemic inflammation is a main hallmark of chronic kidney disease (CKD), but the underlying mechanisms of pathogenesis of CKD-associated systemic inflammation is unclear. Current study was designed to investigate the relationship between indoxyl sulphate (IS) and CKD-associated systemic inflammation along with the protective effects of Klotho in CKD.

METHODS

IS serum levels from patients were detected by high-performance liquid chromatography (HPLC), and Serum Klotho, IL-6 and TNF-α were measured separately by ELISA and Real-Time PCR analysis. Monocytes were incubated with or without Klotho, while the expressions of retinoic acid-inducible gene I (RIG-I) and NF-κB were analyzed through Western blot assay. Heterozygous kl/kl (kl/+) mice or WT mice were treated with 5/6 renal damage. Thereafter, the CKD mice were intraperitoneally injected with recombinant Klotho protein or PBS.

KEY FINDINGS

It shows that in 286 CKD patients, the serum levels of inflammatory factors were positively related with IS, but negatively related with Klotho. Klotho significantly inhibited IS-induced RIG-I/NF-κB activation and productions of both IL-6 and TNF-α in cultured monocytes. In vivo, along with the increase of IS and decrease of Klotho in the serum, the activation of RIG-I/NF-κB signaling was observed in peripheral blood monocytes in both CKD mice and patients. Notably, higher levels of IL-6 and TNF-α were detected in kl+/- mice given CKD. Klotho administration has evidently attenuated RIG-I/NF-κB activation in monocytes and systemic inflammation in CKD mice.

SIGNIFICANCE

The findings suggest that Klotho can suppress CKD-associated systemic inflammation through inhibiting IS-induced RIG-1/NF-κB activation and monocyte inflammatory factor release.

Plasma Klotho concentration is associated with the presence, burden and progression of cerebral small vessel disease in patients with acute ischaemic stroke

Klotho is a soluble or membrane-bound anti-aging protein, whose protective actions are important for a prudential function of many organs. Because Klotho and cerebral small vessel disease (SVD) are associated with ageing process and endothelial dysfunction, it is possible that Klotho has an association with cerebral SVD. We aimed to investigate the association of plasma Klotho concentration with the presence, burden and progression of cerebral SVD. We prospectively enrolled 262 patients with first-ever acute cerebral infarction, performed brain MRI and collected their blood samples within 24 hours of admission. An enzyme-linked immunosorbent assay was used for evaluating plasma Klotho concentration. We estimated the total SVD score of each patient after determining the presence and burden of high-grade white matter hyperintensities (HWMHs), cerebral microbleeds (CMBs), high-grade perivascular spaces (HPVSs) and asymptomatic lacunar infarctions (ALIs). Univariate and multivariate analyses were conducted to investigate association of Klotho with cerebral SVD and the total SVD score. Of the 262 patients, 152 (58.0%) were men. The mean age of these patients was 64.7 years. The mean ± standard deviation of plasma Klotho concentration was 329.8 ± 194.1 pg/mL. In multivariate analysis, plasma Klotho concentration was negatively associated with the presence of HWMHs [Odds ratio (OR): 0.13, p = 0.047], HPVSs (OR: 0.22, p = 0.024) and ALIs (OR: 0.53, p = 0.021) but not associated with the presence of CMBs (OR: 0.39, p = 0.404). Plasma Klotho concentration was also negatively related to the total SVD score (unstandardized coefficients beta: −0.895, standard error = 0.317, p = 0.005, R² = 0.239). Furthermore, plasma Klotho concentration was negatively related to the presence (OR: 0.75, 95% CI: 0.59–0.96, p = 0.025) and severity of cerebral SVD progression (OR: 0.72, 95% CI: 0.56–0.92, p = 0.009). In conclusion, plasma Klotho concentration was negatively associated with the presence, burden and progression of cerebral SVD.

Plasma Klotho and Frailty in Older Adults: Findings From the InCHIANTI Study

BACKGROUND

The hormone klotho, encoded by the gene klotho, is primarily expressed in the kidney and choroid plexus of the brain. Higher klotho concentrations have been linked to better physical performance; however, it is unknown whether klotho relates to frailty status in older adults.

METHODS

Plasma klotho was measured in 774 participants aged ≥65 years enrolled in InCHIANTI, a prospective cohort study comprising Italian adults. Frailty status was assessed at 3 and 6 years after enrollment. Frailty was defined as presence of at least three out of five criteria of unintentional weight loss, exhaustion, sedentariness, muscle weakness, and slow walking speed; prefrailty was defined as presence of one or two criteria; and robustness was defined as zero criteria. We assessed whether plasma klotho concentrations measured at the 3-year visit related to frailty.

RESULTS

Each additional natural logarithm of klotho (pg/mL) was associated with lower odds of frailty versus robustness after adjustment for covariates (odds ratio [OR] 0.46; 95% confidence interval 0.21, 0.98; p-value = .045). Higher klotho was particularly associated with lower odds of exhaustion (OR 0.57; 95% CI 0.36, 0.89; p-value = .014). Participants with higher klotho also had lower estimated odds of weight loss and weakness, but these findings were not statistically significant.

CONCLUSIONS

Higher plasma klotho concentrations were associated with lower likelihoods of frailty and particularly exhaustion. Future studies should investigate modifiable mechanisms through which klotho may affect the frailty syndrome.

Plasmatic Klotho and FGF23 Levels as Biomarkers of CKD-Associated Cardiac Disease in Type 2 Diabetic Patients

Background: Research over the past decade has focused on the role of Klotho as a cardio protective agent that prevents the effects of aging on the heart and reduces the burden of cardiovascular disease CVD. The role of the interaction between fibroblast growth factor 23-(FGF-23)/Klotho in Klotho-mediated actions is still under debate. The main objective was to ascertain the potential use of plasmatic Klotho and FGF23 as markers for CKD-associated cardiac disease and mortality. Methods: This was a prospective analysis conducted in an outpatient diabetic nephropathy clinic, enrolling 107 diabetic patients with stage 2–3 CKD. Patients were divided into three groups according to their left ventricular mass index and relative wall thickness. Results: Multinomial regression analysis demonstrated that low Klotho and higher FGF-23 levels were linked to a greater risk of concentric hypertrophy. In the generalized linear model (GLM), Klotho, FGF-23 and cardiac geometry groups were statistically significant as independent variables of cardiovascular hospitalization (p = 0.007). According to the Cox regression model, fatal cardiovascular events were associated with the following cardiac geometric classifications; eccentric hypertrophy (p = 0.050); concentric hypertrophy (p = 0.041), and serum phosphate ≥ 3.6 mg/dL (p = 0.025), FGF-23 ≥ 168 (p = 0.0149), α-klotho < 313 (p = 0.044). Conclusions: In our population, Klotho and FGF23 are associated with cardiovascular risk in the early stages of CKD.

Clinical significance of fibroblast growth factor-23 and soluble alpha klotho in different stages of chronic kidney disease

Most chronic kidney disease (CKD) biomarkers in the current clinical use are not sensitive enough and cannot be used to identify the early stage of the disease. Klotho is a transmembrane protein predominantly expressed in the renal tubules and implicated in managing phosphate homeostasis, together with fibroblast growth factor-23 (FGF-23); a bone-derived protein that increases urinary phosphate excretion. The present study was carried out on 50 patients CKD with different etiologies referred to the Internal Medicine Department and Out Patient Clinic of Tanta University Hospitals and 30 apparently healthy individuals of matched age and sex as a control group. They were subjected to the following assessment: detailed history taking, careful clinical examination, and laboratory investigations, including urea, creatinine, estimated glomerular filtration rate (eGFR), serum electrolytes, urinary albumin, urinary phosphorus (U-Ph), and specific laboratory tests for: Alpha Klotho (α-klotho) and FGF-23 by using ELISA technique. The present study shows that the mean value of serum creatinine, urea, phosphorus, urinary albumin, and FGF-23 were significantly increased, whereas there was a significant decrease in the mean value of eGFR, calcium, and U-Ph in the patients with CKD when compared with control group. Plasma level of serum α-klotho is significantly decreased in all patients with CKD when compared to the control group and there was a significant positive correlation between serum α-klotho level and eGFR, serum calcium level and U-Ph level. Plasma level of serum α-klotho is significantly decreased in all patients with CKD and serum α-klotho can be used as a good marker for early diagnosis and staging of CKD.

Serum Heparanase Level Is Decreased in Stable Coronary Artery Disease

OBJECTIVE

Heparanase (HPA), mammalian endo-β-D-glu-cu-ronidase, separates heparan sulfate chains of proteoglycans and changes the structure of the extracellular matrix. We investigated whether serum levels of HPA differ in patients with stable coronary artery disease (SCAD) and subjects with normal coronary arteries.

METHODS

This study enrolled 92 patients with SCAD and 34 controls with normal coronary arteries. Levels of HPA were measured by a commercially available human HPA enzyme-linked immunosorbent assay kit.

RESULTS

Serum HPA levels were significantly lower in the SCAD group (137.5 [104.1-178.9] vs. 198.8 [178.2-244.9] pg/mL; p < 0.001). Serum HPA levels were significantly higher in subjects with diabetes mellitus (DM) compared to those without DM (p = 0.008). Levels of HPA were lower in the SCAD group, both in the diabetic and nondiabetic subgroups, as compared to controls (p < 0.001 for both subgroups). Levels of HPA positively correlated with fasting blood glucose (FBG) (r: 0.42; p < 0.001). In multiple logistic regression analysis, serum HPA level (odds ratio [OR]: 0.975; 95% confidence interval [CI]: 0.966, 0.985; p < 0.001) and FBG (OR: 1.028; 95% CI: 1.010, 1.047; p = 0.002) were independently associated with SCAD. The receiver operating characteristic curve showed that HPA levels less than 160.6 pg/mL predicted SCAD with 65% sensitivity and 97% specificity (AUC: 0.80; 95% CI: 0.728, 0.878; p < 0.001).

CONCLUSION

Diabetes and FBG levels were closely associated with serum levels of HPA. Low serum levels of HPA may predict SCAD in both diabetic and nondiabetic populations.

[Effect of Ronghuang Granule on serum FGF23, FGFRs and Klotho in non-dialysis patients with CKD-MBD and kidney deficiency and damp-heat syndrome]

OBJECTIVE

To observe the effect of Ronghuang granule on serum fibroblast growth factor 23 (FGF23), fibroblast growth factor receptor (FGFRs) and Klotho protein levels in non-dialysis patients with chronic kidney disease-mineral and bone disorder (CKD-MBD) and kidney deficiency and damp heat syndrome.

METHODS

Seventy non-dialysis CKD-MBD patients with kidney deficiency and dampness-heat syndrome were randomized into control group (n=35) and treatment group (n=35). All the patients were given routine treatment combined with traditional Chinese medicine retention enema, and the patients in the treatment group received additional Ronghuang granule treatment (3 times a day). After the 12-week treatments, the patients were examined for changes of TCM syndromes. Serum levels of Ca, P, parathyroid hormone (iPTH), FGF23, FGFRs and Klotho proteins were detected before and after treatment. These parameters were also examined in 20 healthy volunteers.

RESULTS

Sixty-five patients completed the study, including 33 in the control group and 32 in the treatment group. The patients in the treatment group showed significantly better treatment responses than those in the control group (P &lt; 0.05 or 0.01). At 4, 8, and 12 weeks of treatment, the patients in the treatment group had significantly lowered scores of TCM syndromes compared with the score before treatment (P &lt; 0.05 or 0.01), while in the control group, significant reduction of the scores occurred only at 12 weeks (P &lt; 0.05); at each of the time points, the treatment group had significantly greater reductions in the score than the control group (P &lt; 0.01). Significant improvements in serum Ca, P and iPTH levels were observed at 4, 8, and 12 weeks in the treatment group (P &lt; 0.05) but only at 12 weeks in the control group (P &lt; 0.05). The patients in the control and treatment groups all showed elevated serum levels of FGF23, FGFRs and Klotho protein compared with the normal subjects (P &lt; 0.01); FGF23, FGFRs and Klotho levels were significantly reduced in the treatment group (P &lt; 0.05) but remained unchanged in the control group (P&gt;0.05), showing significant differences between the two groups.

CONCLUSIONS

Ronghuang granule improves the clinical symptoms of non-dialysis CKD-MBD patients with kidney deficiency and dampness heat syndrome by reducing serum levels of FGF23, FGFRs and Klotho, improving calcium and phosphorus metabolism disorder, and inhibiting secondary hyperparathyroidism.

Effects of L-Carnitine on Mineral Metabolism in the Multicentre, Randomized, Double Blind, Placebo-Controlled CARNIDIAL Trial

BACKGROUND

The use of L-carnitine has been proposed in haemodialysis (HD) when deficiency is present to improve anaemia resistant to erythropoietin stimulating agent, intradialytic hypotension or cardiac failure. We tested the effects of L-carnitine supplementation on parameters of chronic kidney disease-mineral bone disorder.

METHODS

CARNIDIAL was a randomized, double-blinded trial having included 92 incident HD subjects for a 1-year period to receive L-carnitine versus placebo. Determinant factors of C-terminal fibroblast growth factor 23 (cFGF23) and intact FGF23 were studied including Klotho level. The L-carnitine effect on mineral metabolism was analyzed between groups by mixed linear models for repeated measurements.

RESULTS

Klotho was below the lower limit of quantification (LLOQ) in 55% of the 163 samples. In multivariate analysis, cFGF23 was positively correlated with calcium and phosphate and was higher in subjects having Klotho > LLOQ. No correlation existed between Klotho and phosphate and phosphate was even higher in subjects having Klotho > LLOQ (p < 0.001). Both forms of FGF23 were not related to iron markers nor to IV iron dose. No L-carnitine effect was detected on parathyroid hormone (PTH) or FGF23 during the study period where PTH slightly decreased over time, whereas FGF23 increased. But calcium and phosphate increased more in the L-carnitine group.

CONCLUSION

L-carnitine supplementation increased calcium and phosphate plasma concentrations with no detected downregulation effect on PTH and FGF23. (Clinical Trial 00322322, May 5, 2006).

Association Between Plasma Concentration of Klotho Protein, Osteocalcin, Leptin, Adiponectin, and Bone Mineral Density in Patients with Chronic Kidney Disease

Patients with early-stage chronic kidney disease (CKD) are susceptible to changes in metabolic processes. Partial loss of kidney function leads to homoeostatic disturbances in bone and fatty tissue. The aim of this study was to investigate the association between plasma concentrations of Klotho protein, FGF23, leptin, adiponectin, osteocalcin, and bone mineral density (BMD) in patients with CKD in the pre-dialysis period. The study involved 52 patients with CKD and 23 patients with no kidney disease. In both groups, BMD, body mass index and serum or plasma concentrations of lipids, glucose, creatinine, calcium, phosphorus, parathormone, leptin, adiponectin, osteocalcin, Klotho, and FGF23 were measured. The group with CKD had statistically significant higher concentrations of leptin (p<0.001), parathormone (p<0.001), and osteocalcin (p<0.001) in comparison with the control group. Patients with CKD also had statistically significant lower BMD in the femoral neck in comparison with the control group. Osteocalcin correlated negatively with BMD. The results of our study suggest that elevated osteocalcin is the most sensitive marker of decreased bone mass in patients with CKD. Osteocalcin correlated negatively with BMD and GFR. The loss of bone mass in CKD patients was greatest in the femoral neck.

Clinical implication of alterations in serum Klotho levels in patients with type 2 diabetes mellitus and its associated complications

AIM

To investigate the clinical significance of serum α-Klotho and β-Klotho levels in patients with type 2 diabetes mellitus (T2DM) and its associated complications.

METHODS

Serum α-Klotho and β-Klotho levels were measured using an ELISA kit in 817 individuals, including 127 with T2DM, 106 with diabetic nephropathy, 99 with diabetic retinopathy, 108 with diabetic neuropathy, 102 with diabetic foot disease, 135 with T2DM and more than one complication and 140 healthy controls.

RESULTS

Both α-Klotho and β-Klotho levels were significantly decreased in the T2DM group and the groups with associated complications compared with the levels in control group. The differences between the T2DM group and the T2DM with complications groups were not significant, except between the diabetic nephropathy group and the other diabetic complications groups. In addition, α-Klotho and β-Klotho levels were negatively correlated with serum fructosamine and HbA1c but were not associated with serum glucose in the model including all participants. Moreover, decreases in α-Klotho and β-Klotho levels in the high glucose-exposed cell culture model, which was dependent on glucose exposure time, were confirmed.

CONCLUSIONS

Levels of α-Klotho and β-Klotho were downregulated in patients in the T2DM and complications groups. Our findings indicate that serum Klotho levels were associated with the development of T2DM, and long-term control of blood glucose will be beneficial in ameliorating changes to α-Klotho and β-Klotho levels in patients with T2DM and complications.

FGF23-klotho axis, bone fractures, and arterial stiffness in dialysis: a case-control study

We performed a case-control study on 130 age- and sex-matched hemodialysis patients. In multivariate analysis, we observed that FGF23 levels were associated with fracture incidence and that soluble α-klotho levels were associated with the aortic-brachial arterial stiffness ratio.

INTRODUCTION

New bone markers such as sclerostin, Dickkopf-related protein 1 (DKK1), fibroblast growth factor-23 (FGF23), and α-klotho have been identified as potential key players in bone and vascular abnormalities of chronic kidney disease. Therefore, we aimed to assess whether these markers are associated with fractures, bone metabolism, and vascular stiffness in dialysis patients.

METHODS

In a prospective hemodialysis cohort, where plasma samples and vascular assessment were performed at baseline, we matched patients who experienced a fracture during follow-up with sex- and age-matched non-fractured patients on a 1:4 ratio. Sclerostin, DKK1, α-klotho, FGF23, and markers of bone formation (alkaline phosphatase and procollagen type 1-N terminal propeptide [P1NP]) and bone resorption (tartrate-resistant acid phosphatase 5b [TRAP5b]) were measured in baseline plasma samples. Aortic-brachial pulse wave velocity ratio, a blood pressure independent measure of arterial stiffness, was used to assess vascular stiffness at baseline.

RESULTS

We included 130 hemodialysis patients (26 fractured, 104 non-fractured) with a median follow-up of 42 months and a median age of 72 years. In multivariate Cox regression models, high FGF23 levels were associated with increased fracture incidence (adjusted HR = 2.97; 95% CI 1.18, 7.43). α-Klotho levels were associated with bone formation but not resorption markers. In both univariate and multivariable adjusted models, α-klotho levels were inversely associated with the aortic-brachial pulse wave velocity ratio (β = - 0.070; 95% CI - 0.133, - 0.006).

CONCLUSIONS

These results suggest a role for FGF23/klotho axis on bone and vascular metabolism in dialysis populations.

Effect of Sevelamer on Serum Levels of Klotho and Soluble Tumor Necrosis Factor-like Weak Inducer of Apoptosis in Rats With Adenine-induced Chronic Kidney Disease

INTRODUCTION

Nontraditional risk factors for cardiovascular disease (CVD), including mineral disorder, high fibroblast growth factor 23 (FGF23), low klotho, and low soluble TWEAK could predict the incipient risk of CVD in chronic kidney disease (CKD). The present study evaluates the effect of sevelamer on soluble tumor necrosis factor-like weak inducer of apoptosis (TWEAK), and klotho levels in adenine-induced CKD rats.

METHODS AND MATERIALS

Normal control rats without sevelamer were compared with 3 groups of adenine-induced CKD rats, including CKD rats without sevelamer, CKD rats treated with 3% sevelamer, and rats receiving adenine and 3% sevelamer concurrently. After 4 weeks of sevelamer treatment, serum levels of klotho and soluble TWEAK were measured, along with biochemical parameters related to kidney function.

RESULTS

Sevelamer significantly reduced serum levels of phosphate and increased serum levels of klotho and soluble TWEAK. Decreased levels of phosphate were negatively correlated with elevated levels of klotho and soluble TWEAK (r = -0.70, P = .003; r = -0.58, P = .02; respectively) in serum.

CONCLUSIONS

Sevelamer successfully reduced serum levels of phosphate, and meanwhile, it led to an elevation in serum levels of klotho and soluble TWEAK in rat models of CKD.

Optimization of the method for α-l-fucosidase, β-d-galactosidase and β-d-glucuronidase determination in serum from hemolyzed blood

PURPOSE

Adaptation of the colorimetric method for the determination of β-d-galactosidase, β-d-glucuronidase and α-l-fucosidase activities in serums from hemolyzed blood, the material currently being discarded.

MATERIALS AND METHODS

The materials included serums from hemolyzed and non-hemolyzed blood, obtained from 26 healthy volunteers. The adaptation of the method involved precipitation of the proteins with trichloroacetic acid after incubating serums with substrates, but before determining the products of enzymatic reactions.

RESULTS

In serums from hemolyzed and non-hemolyzed blood of the same persons, we found high correlations among the results obtained using hemolyzed blood (with adapted) and non-hemolyzed blood (with non-adapted) methods.

CONCLUSION

We are able to determine the β-d-galactosidase, β-d-glucuronidase and α-l-fucosidase activities in serums from hemolyzed blood (with adapted) and non-hemolyzed blood (with non-adapted) methods, with the same accuracy and precision.

Analysis of endocrine hormone metabolism level in a Chinese patient with mucopolysaccharidosis IVA: A case report

RATIONALE

Mucopolysaccharidosis IVA (Morquio A) is a catabolic mucopolysaccharide disorder caused by galactose-6-sulfate sulfatase deficiency. It is an autosomal recessive inherited disease. Previous reports on clinical characteristics of Morquio A mainly focused on growth retardation, skeletal deformities, and organ damage in children and adolescents, while the effects of mucopolysaccharide metabolism disorders on endocrine hormone metabolism level have not been reported. Herein, we reported the endocrine hormone metabolism in a case diagnosed as Morquio A.

PATIENT CONCERNS

The patient was a 17-year-old girl with growth retardation, hearing loss, and severe skeletal dysplasia(scoliosis and chicken breast), and was evaluated to have normal nervous system function and intelligence by physicians.

DIAGNOSES

She was diagnosed as Morquio A based on gene analysis, mucopolysaccharide-related enzymes and her clinical features.

INTERVENTIONS

The patient didn't accepted the enzyme replacement therapy.

OUTCOMES

She had a homozygous mutation of the GALNS gene. The b-glucuronidase content in the blood was reduced. The serum sodium, serum adrenocorticotropic hormone, and cortisol rhythms (8 AM) were decreased. The levels of PRA(plasma renin activity) , PAII(plasma angiotensin II), and PALD(plasma aldosterone) were elevated. Bone mineral density suggests osteoporosis. There were no abnormalities in bone metabolism indicators, growth hormone, thyroid hormone, and sex hormones. In summary, the level of endocrine hormones in patients with mucopolysaccharidosis IV changes.

LESSONS

This is the report on endocrine hormone level in a patient with mucopolysaccharidosis IV in China. Due to the disease may have relatively incomplete adrenal function, which provides a basis for future understanding and diagnosis of this disease.

Impact of cigarette smoking cessation on plasma α-klotho levels

Smoking cessation reduces the risk of cardiovascular disease and improves clinical outcomes. We studied the effect of smoking cessation on plasma levels of α-klotho, which is an antiaging protein. We treated 28 smokers (male:female = 23:5, 46 ± 12 years) with varenicline (n = 14) or a transdermal nicotine patch (n = 14) as part of a 12-week smoking cessation program (the VN-SEESAW Study). Pulse rate, blood pressure, plasma levels of α-klotho, fibroblast growth factor (FGF)-19, FGF-21, hemoglobin (Hb), and expiratory carbon monoxide (CO) concentration were measured before and after the antismoking intervention. Smoking cessation significantly decreased pulse rate, α-klotho, Hb, and CO concentration, but not FGF-19 or FGF-21 in all subjects. On the contrary, body mass index significantly increased after the intervention. Changes in α-klotho levels (values at week 12 - values at week 0) were negatively associated with α-klotho levels at week 0 and positively associated with changes in Hb levels. In addition, the successful smoking cessation group (n = 21) showed significant reductions in pulse rate, systolic blood pressure, α-klotho, Hb, and CO concentration. In conclusion, smoking cessation significantly decreased serum levels of the antiaging molecule α-klotho. Our results are consistent with a previous report that an increase in α-klotho might be a compensatory response to smoking stress.

Circulating Klotho levels can predict long-term macrovascular outcomes in type 2 diabetic patients

BACKGROUND AND AIMS

Type 2 diabetes is a global health problem that is associated with a wide variety of vascular complications and associated morbidity and mortality. Klotho is an enzyme and transmembrane protein, and increasing evidence suggests that Klotho may contribute to reduced oxidative stress, improved endothelial function, and vasoprotection. To date, the physiological role of Klotho in vascular complications associated with diabetes is unclear.

METHODS

We prospectively recruited 252 patients with type 2 diabetes, who visited an outpatient clinic at our hospital between 2009 and 2011. Patients in the top and bottom tertiles of circulating Klotho levels were enrolled for analysis.

RESULTS

Of the 168 patients enrolled, 45.8% were male, the mean age was 57.2 years, and the average duration of diabetes was 7.58 years. In multiple regression analysis, a high Klotho level was associated with a reduced risk of developing coronary artery disease and cerebrovascular accidents. Klotho level was also an independent predictor for the development of macroangiopathies within the 7-year study period.

CONCLUSIONS

Our results suggest that circulating Klotho level is a predictor of long-term macrovascular outcomes in patients with type 2 diabetes.

Circulating α-Klotho is Related to Plasma Aldosterone and Its Follow-Up Change Predicts CKD Progression

BACKGROUND/AIMS

We aimed to determine if soluble α-klotho level was an indicator of chronic kidney disease (CKD) progression and whether α-klotho interacted with aldosterone during the course of further renal damage.

METHODS

112 adults with stages 1-5 CKD were enrolled into our cohort study. All of the patients were followed up for 6 years (from January 2010 to December 2015). Serum soluble α-klotho and aldosterone were measured at baseline and at 1.5-years follow-up. The primary outcome was the initiation of renal replacement therapy (RRT) and the secondary outcome was the occurrence of cardio-cerebrovascular events. Long-term progression to RRT and cardio-cerebrovascular events in patients was analyzed with a risk-adjusted Cox proportional hazards regression model. Adjustment included age, gender, eGFR, mean arterial pressure, 24-h protein excretion and the change in α-klotho level from baseline at 1.5-years follow-up.

RESULTS

Baseline circulating α-klotho levels were positively associated with baseline estimated glomerular filtration rate (eGFR; r = 0.224, p = 0.017), but not age, calcium, phosphate, or parathyroid hormone levels. The change in α-klotho level from baseline at 1.5-years follow-up (p = 0.002) was independently associated with renal replace treatment (RRT) initiation after adjustment for age, gender, eGFR, mean arterial pressure, and 24-h protein excretion in Cox regression analysis. Aldosterone levels were positively associated with CKD stage, and were inversely correlated with circulating α-klotho levels.

CONCLUSION

The change in concentration of soluble α-klotho during the 1.5-years follow-up was an indicator of CKD progression. Renal damage associated with a reduction of α-klotho may involve the upregulation of plasma aldosterone. Future studies are needed to validate our findings, and to investigate the underlying mechanism by which α-klotho and aldosterone may cause renal damage.

Reduced Levels of Anti-Ageing Hormone Klotho Predict Renal Function Decline in Type 2 Diabetes

CONTEXT AND OBJECTIVE

Soluble Klotho (sKlotho) is a circulating hormone with cardiovascular-renal protective effects. Whether sKlotho predicts estimated glomerular filtration rate (eGFR) decline in patients with type 2 diabetes mellitus (T2DM) with relatively preserved renal function is unknown.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Single-center observational follow-up study of 101 patients with T2DM and eGFR >45 mL/min [91% on renin angiotensin system (RAS) blockade] followed for a median of 9 years (range, 2 to 13 years).

MAIN OUTCOME

Primary outcome was a >50% decline in eGFR. sKlotho, serum phosphorus, serum calcium, and fibroblast growth factor-23 levels were measured from stored samples collected at baseline. Patients were followed up with standardized clinical and biochemical measurements.

RESULTS

Patients with residual microalbuminuria (MA) despite RAS blockade (n = 53) had significantly lower levels of sKlotho [median, 184.7 pg/mL; interquartile range (IQR), 130.5 to 271.8 pg/mL) compared with patients without MA (n = 39; median, 235.2 pg/mL; IQR, 172.0 to 289.4 pg/mL; P = 0.03). Of the cohort, 21% reached the primary outcome. In a competing risk analysis, a 10% higher sKlotho level reduced the incidence of the primary outcome by 12% (hazard ratio, 0.27; 95% confidence interval, 0.15 to 0.52; P < 0.001] independent of traditional risk factors. Patients with sKlotho below the median of 204.4 pg/mL had nearly a fourfold higher cumulative incidence of the primary outcome compared with those above the median (24% vs 6.2%; P = 0.01).

CONCLUSIONS

In patients with T2DM with relatively preserved eGFR, reduced levels of sKlotho predict renal function decline independent of traditional risk markers. sKlotho is a biomarker of renal dysfunction and a potential treatment target for renoprotection in T2DM.